This story has been updated with a response from the Department of Environmental Quality.
Oregon's Department of Environmental Quality on Thursday released another round of air-monitoring data for early March that it said showed low risks to Portlanders.
The results from four monitors in Southeast Portland and one in North Portland continued showing dramatically lower levels of heavy-metals pollution than were detected in Southeast in October before glassmakers stopped using some metals.
The agency began using a new, looser safety threshold for one metal, nickel, which the monitoring found above an earlier, stricter target.
The latest monitoring from March 1 to March 8 repeatedly found levels of nickel in the air at levels the state said were not unusual, reporting concentrations only slightly above the state's safety goal.
The state had previously said its annual safety goal for the air near glassmakers was 2 nanograms of nickel per cubic meter. At those levels, the pollution would be expected to cause one additional case of cancer from people in the affected area over a lifetime of breathing the air.
But the state now says 4 nanograms are acceptable. With the old target, 11 daily monitoring results would've come in above the goal. Instead, just four did.
The Department of Environmental Quality was slow to explain the change.
The Oregonian/OregonLive asked four agency officials for an explanation Thursday. A spokeswoman, Marcia Danab, steered questions to a lab director, Brian Boling. He referred them to an air-toxics specialist, Sarah Armitage. She said the agency had deliberately chosen the new number, but couldn't explain why.
Armitage later emailed to say the agency decided to use the less restrictive number because it was slated to be adopted as its new safety goal, the result of a five-year review process by a scientific advisory committee.
The more restrictive goal, she wrote, applies to a rare type of the metal associated with refining nickel ore. The state initially used it out of an abundance of caution, she explained. The safety goal for the most commonly occurring type of nickel is 50 nanograms, she said.
"We are using the most scientifically accurate recommended benchmark," she wrote.
A Southeast Portland resident said she was baffled as to why the state would change the safety goal without drawing attention to it.
"When you change a benchmark, there has to be a rationale," said Jessica Applegate, who helped found the Eastside Portland Air Coalition after the glassmakers' pollution was revealed in February. "Nothing is being explained to the public. That's what creates concern."
Nickel has emerged as a metal of particular interest in the ongoing toxic-air scare. The state's response initially focused on two heavy metals, arsenic and cadmium, which October air monitoring found in dangerous levels near a Southeast Portland glassmaker, Bullseye Glass.
State environmental officials have since acknowledged concerns about nickel, too. The metal can cause asthma and lung cancer when inhaled.
When the state struck an agreement on pollution controls last week with a North Portland glassmaker, Uroboros Glass, it included strict provisions setting weekly restrictions nickel's use in unfiltered furnaces.
No such restrictions are in place at Bullseye Glass, which is allowed to continue using nickel in furnaces lacking pollution controls.
— Rob Davis
rdavis@oregonian.com
503.294.7657
